Turbo-molecular pump and method of assembling turbo-molecular pump

Abstract

A turbo-molecular pump has a housing with intake and exhaust ports. A rotary body is enclosed in the housing and has rotor blades of a series of stages formed so that the outside diameter of at least one stage on the exhaust port side is smaller than that on the intake port side. Stator blades are arranged between the rotor blades and spacer rings are arranged between the stator blades to hold the stator blades at predetermined intervals. The spacer rings are formed so that the smallest inside diameter of at least one stage of the spacer rings on the exhaust port side is smaller than the largest outside diameter of the rotor blades. The housing comprises a casing whose inside diameter is constant or whose inside diameter is smaller at the intake port side than at the exhaust port side.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a U.S. national stage application of International Application No. PCT / JP2006 / 312108, filed Jun. 16, 2006, claiming a priority date of Jun. 22, 2005, and published in a non-English language.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a turbo-molecular pump used, for example, for evacuation in a vacuum chamber and a method of assembling the turbo-molecular pump.[0004]2. Description of the Related Art[0005]Equipment using a vacuum device which accomplishes evacuation by using a vacuum pump and the interior of which is kept in vacuum includes semiconductor manufacturing equipment, liquid crystal manufacturing equipment, electron microscopes, surface analyzers, microfabrication equipment, and the like.[0006]Also, among various types of vacuum pumps, a turbo-molecular pump is often used to realize a high-vacuum environment.[0007]The turbo-molecular pump is configured so t...

AI Technical Summary

Benefits of technology

This design enhances assembling efficiency and strength by ensuring proper clearance and alignment, preventing deformation and interference, and improving the pump's durability by reducing centrifugal stress on rotor blades.

Problems solved by technology

However, the above-described turbo-molecular pump having a construction such that the outside diameters of the rotor blades on the exhaust port side are smaller than the outside diameters of the rotor blades on the intake port side as described in Patent Document 1 has a problem in that a method of assembling stator blades and spacer rings is restricted as compared with a turbo-molecular pump in which the outside diameters of rotor blades in all stages are equal.

Therefore, the stator blades cannot be piled up one after another from the downside (from the exhaust port side) while the spacer rings are fitted from the intake port side of rotor blade because the rotor blade on the intake port side and the spacer ring on the exhaust port side interfere with each other.

However, for such a halved spacer ring, at the time of fabrication, that is, at the time of cutting, the cut surface may be deformed, or the external shape may be distorted.

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